Radel-based membranes with pyridine and imidazole side groups for high temperature polymer electrolyte fuel cells

Steffen Hink, Ngoc My Hanh Duong, Dirk Henkensmeier, Jin Young Kim, Jong Hyun Jang, Hyoung Juhn Kim, Jonghee Han, SukWoo Nam

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11 Citations (Scopus)

Abstract

Polysulfone-based membranes with pyridine (PY) side chains, crosslinked by imidazole (IM) groups, are synthesised, doped with phosphoric acid (PA) and characterised in the hydrogen/air fuel cell at 160 °C. It is shown that the bisphenol A (BPA) group of Udel P-3500 (Solvay) acts as a breaking point, and Radel R-5000 NT (Solvay)-based membranes, in which BPA is substituted for biphenyl, show superior stability. Undoped membranes show thermal stability of up to 330 °C (3% weight loss, 10 °C/min, nitrogen). PA-doped membranes: The weight gain during acid doping is limited by the high crosslink density, and independent of the doping temperature. By varying the ratio of pyridine to imidazole units from 2:1 to 9:1, the PA uptake can be controlled between 200 and 500 wt%, respectively. The Young modulus increases with the crosslinking density from 12 to 129 MPa. Proton conductivity of the PY/IM 2:1 membrane at 160 °C reaches 59 mS/cm. In the fuel cell, the PY/IM 2:1 membrane achieved a potential of ca. 500 mV at 0.2 A/cm<sup>2</sup>. After 430 h (330 h at 0.2 A/cm<sup>2</sup>, then 0.4 A/cm<sup>2</sup>), the cell failed, and postmortem analysis suggested severe chemical degradation. Washing the membrane with ammonia solution before doping increased the stability further.

Original languageEnglish
Pages (from-to)80-85
Number of pages6
JournalSolid State Ionics
Volume275
DOIs
Publication statusPublished - 2015 Jul 1

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Keywords

  • Crosslinked membrane
  • HT PEMFC
  • Phosphoric acid doping
  • Pyridine
  • Radel

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Chemistry(all)

Cite this

Hink, S., Duong, N. M. H., Henkensmeier, D., Kim, J. Y., Jang, J. H., Kim, H. J., ... Nam, S. (2015). Radel-based membranes with pyridine and imidazole side groups for high temperature polymer electrolyte fuel cells. Solid State Ionics, 275, 80-85. https://doi.org/10.1016/j.ssi.2015.03.026